DE102005039182A1 - Low insertion force connector part, method of making same and substrate for same - Google Patents

Abstract

The invention provides low insertion force connector parts. A self-assembled monolayer is deposited on the surface of the connector parts. The coated connector parts do not require a special lever for adjusting the contact pressure. The connector parts are easy to produce without cost increase and of small size. They do not increase the contact resistance, and they are easy to connect with low insertion force, so that they are used as connectors of vehicles.

Description

The The invention relates to a low insertion force connector part, a method for Making it and a substrate for the same.

excellence of electrical appliances and the diversification of vehicle equipment requires more connector parts.

This causes a big one Force to connect the connectors. It is then necessary to reduce the power to join them.

JP-2002-110276-A, JP-2001-257022-A and JP-H05-121128-A disclose a force reduction of connector part springs to reduce the contact force. However, this causes an increase in contact resistance.

JP-2002-280112-A and JP-2001-237026-A disclose a connector, which with compressed a lever is after the connectors with low compression force have been joined together. However, this leads to an increase the cost.

Around to reduce the sliding friction is applied to the sliding surface of a connector part, a lubricant, e.g. Oil, applied or a multi-layer coating shaped. However, these methods do not give sufficient effects but lead an increase in costs.

JP-2002-088496-A and JP-H11-317253-A disclose application of a MoS ₂ lubricating film on the sliding surface of a connector part. However, this causes an increase in contact resistance.

One The aim of the invention is to provide a low insertion force connector part. The connector part is easy to manufacture and by means of a significant low force without using one adjustment lever with another Connector part to connect. The connector part causes no increase in contact resistance.

According to claim 1 of the invention has a low insertion force connector part a self-assembled monolayer (SAM) on the sliding surface thereof on.

According to claim FIG. 4 of the invention includes a method of manufacturing a low insertion force connector part a step of forming a self-assembled monolayer on the sliding surface of it.

According to claim 7 of the invention includes a substrate for a low insertion force connector part a self-assembled monolayer on the sliding surface thereof on.

1 shows an XPS (X-ray photoelectron spectroscopy) spectrum of an uncoated substrate,

2A shows an enlarged spectrum of the carbon C1s peak,

2 B shows an enlarged spectrum of oxygen O1s peaks,

2C shows an enlarged spectrum of the tin Sn3d peak,

2D shows an enlarged spectrum of the copper Cu2p peak,

2E shows an enlarged spectrum of the sulfur S2t peak,

3 shows an XPS spectrum of a coated substrate of Example 1,

4A shows an enlarged spectrum of carbon C1s peaks,

4B shows an enlarged spectrum of oxygen O1s peaks,

4C shows an enlarged spectrum of the tin Sn3d peak,

4D shows an enlarged spectrum of the sulfur S2p peak,

5 shows the change of the contact resistance over the contact force for the coated substrate A and the uncoated substrate of Example 1,

6 illustrates a method of measuring frictional resistance

7A shows the coefficient of friction versus displacement for the uncoated substrate of Example 1, measuring twice,

7B shows the coefficient of friction over the displacement for the coated substrate of Example 1, wherein the measurement is carried out twice was led,

8th shows an Auger electron spectroscopy (AES) spectrum for a coated substrate of Example 2,

9 shows a change in load over the sliding distance when conventional connectors are connected together,

10 shows that the plug-in part is inserted from a plug into the spring of a socket when the conventional plug-in connectors are connected together,

11 shows the load change when the connectors in Example 2 are connected together,

12A shows an XPS spectrum of a coated substrate of Example 3,

12B shows an enlarged spectrum of the carbon C1s peak,

12C shows an enlarged spectrum of the sulfur S2p peak,

13A shows an XPS spectrum of an uncoated substrate of Example 3,

13B shows an enlarged spectrum of carbon C1s peaks,

13C shows an enlarged spectrum of the sulfur S2c peak, and

14 shows the contact resistance over the contact force for the coated substrate and uncoated substrate.

A self-assembled monolayer according to the invention is by means of a chemical bonding of organic molecules with metals of the connector part surface on the connector part surface shaped. The organic molecules form a monolayer, which is over van der Waals forces aligned or oriented molecules. The self-assembled or self-assembled monolayer is dense and firm and gives a low frictional resistance and a high surface protection.

The self-assembled monolayer is at least on the sliding surface of the connector part metal, such. Copper, including copper alloys, Gold, silver, tin or a coating of it, shaped.

One Substrate made of copper or a copper alloy, which is cheap and is highly conductive, is used, and a tin layer is by means of Plating on the surface formed by the substrate. The oxide film of the tin layer is thin and light replace, so that a fresh metal surface is easily obtained.

If the sliding surface contaminated by the connector part metal, oxidized or sulfurized is, the training of the self-assembled monolayer is very impaired so cleaning is necessary to the metal oxide and the metal sulfide to remove. For cleaning, acidic solutions such. As sulfuric acid, hydrochloric acid and Nitric acid, used.

Of the Tin oxide film is stronger (denser) than that of copper oxide, so it is desirable for cleaning the surface, which contains tin, nitric acid to use.

Other acids as nitric acid can be oxides barely remove. They produce by-products after removal of the oxides and cause an increase in surface roughness. The by-products prevent the formation of self-assembled monolayer, so that the friction reduction is prevented.

To the Cleaning the tin surface it is desirable to have a nitric acid concentration of 13Ma% to use up to 17Ma% with a cleaning time of 8 to 13 seconds. It is worth the solution while cleaning the tin surface to stir. Under this condition, the best state of the tin surface becomes Forms of self-assembled monolayer provided.

Further at least one cleaning method with a solvent, Water or an alkaline liquid before and after the acid purification process be combined with this.

If the sliding surface is formed with gold, platinum or palladium, which hardly oxides or Sulfides on the surface mold it, it is possible that To skip cleaning. However, if rust or mold stains, such. As organic substances adhere to the metal surface, it is desirable to area to clean before making the self-assembled monolayer, to adversely affect the properties of the monolayer, such as As the orientation to avoid.

Organic molecules for forming the self-assembled monolayer on the metal surface have adsorption functional groups. Specific absorption functional groups are organic thiol substances (R ₁ SH) with a thiol radical, disulfide compounds (R ₁ SSR ₂ ) with ei a disulfide radical and sulfide compounds (R ₁ SR ₂ ) with a sulfide radical. Here R ₁ and R _{2 are} straight-chain hydrocarbon groups, such as. B. - (CH ₂ ) _n CH ₃ , fluorine-substituted hydrocarbon groups, such as. B. - (CH ₂ ) _n CF ₃ , - (CH ₂ ) _n CF ₃ - (CH ₂ ) _n (CH ₂ ) _m CF ₃ , wherein fluorine substitutes at least one hydrogen or a hydrogen atom in the hydrocarbon group, carboxyl-substituted hydrocarbon groups, such as B. - (CH ₂ ) _n COOH, wherein the carboxyl group substituted at least one hydrogen in the hydrocarbon group, amino-substituted hydrocarbon groups, such as. B. - (CH ₂ ) _n NH ₂ , wherein the amino group substituted at least one hydrogen in the hydrocarbon group, or hydroxy-substituted hydrocarbon groups, such as. B. - (CH ₂ ) _n CH ₂ OH, wherein the hydroxy group substitutes at least one hydrogen in the hydrocarbon group. Here, n and m are natural numbers equal to or greater than 3.

The R in the organic thiol substances (R ₁ SH) is an alkyl group of - (CH ₂ ) _n CH ₃ , a fluorinated alkyl group of - (CH ₂ ) _n CF ₃ , an aliphatic carboxylic acid group of - (CH ₂ ) _n COOH or a Aliphatic alcohol group of - (CH ₂ ) _n CH ₂ OH, where n is a natural number equal to or greater than 3.

Such an organic thiol substance is dissolved in an alcoholic solvent, such as For example, ethanol, methanol or isopropyl alcohol dissolved to a thiol-alcohol solution receive. The sliding portion of the connector part is immersed in or used with the solution, around the self-assembled monolayer on the surface of to form the connector part.

Next The immersion process can be self-assembled or self-assembling Monolayer by means of vapor deposition by means of contacting the Sliding portion of the connector part with the vapor of organic Thiol substance are formed.

Example 1: Substrate

<Formation of self-assembled monolayer>

It a tin-plated copper alloy substrate (product name NB109: Dowa Mining Co., Ltd.) commonly used for connector parts is used, with a thickness of 0.2 mm.

When a pretreatment was the substrate for 10 seconds in a 15Ma% Dipped nitric acid solution, for a fresh surface from the tin metal by removing the oxide layer from the substrate surface.

One Octadecanethiol (available Aldrich Corporation) was dissolved in 99.5% ethanol to give a solution of 1mM. The pretreated copper alloy substrate was for 48 hours in the solution immersed and cleaned by means of ultrasonic cleaning in ethanol.

<Detection of self-assembled monolayer>

A View of Coated Substrate A by XPS (X-ray Photoelectron Spectroscopy) confirmed a component of octadecanethiol on the surface of the tin plated substrate.

1 Figure 12 shows an XPS spectrum of the uncoated substrate, the one pretreated only with nitric acid. The 2A to 2E show enlarged spectra of the carbon C1s peak ( 2A ), the oxygen O1s peak ( 2 B ), the tin Sn3d peak ( 2C ) or copper Cu2p peak ( 2D ) from 1 , 3 shows an XPS spectrum of the coated substrate A. The 4A to 4D show enlarged spectra of the carbon C1s peak ( 4A ), the oxygen O1s peak ( 4B ), the tin Sn3d peak ( 4C ) or the sulfur S2p peak ( 4D ) from 3 ,

With The XPS consideration was found to be self-assembled Monolayer was not removed by ultrasonic cleaning and with the tin-plated surface connected is.

<Evaluation of contact resistance>

Of the Contact resistance of the coated substrate was measured and the effect on electrical properties was studied. Two each Samples were for measured the uncoated substrate and the coated substrate. The value was compared with that of the uncoated substrate.

The Contact load from a stamp on the coated substrate A was from 0.908 - 9.8 N, and the contact resistance (R) was measured with the four-sensor method (four-probe method). Of the Resistance was obtained from the equation R = V / I (Eqn.1), where V is the voltage difference between the sensors or contacts, and where I is the applied current.

5 shows the result. The test conditions were as follows: contact weight: 0.098 - 9.8 N, applied current (I): 10 mA, radius of the punch end: 1.0 mm. The stamp is made of reflow tin plated copper alloy. The stamp was thoroughly cleaned with trichloroethane before measurement.

As in 5 As shown, the contact resistance of the coated substrate at a contact load of 5N is 0.9-4mΩ, which corresponds to the closing state of a connector part actually used, and has almost the same value as that of the uncoated substrate. Although the self-assembled monolayer is formed, the contact resistance is hardly changed. It is believed that the self-assembled monolayer has a thickness equal to or less than a few dozen angstroms and tunneling current may occur. The self-assembled monolayer almost does not affect the electrical properties and is believed to be suitable for use on electrical contact sections such as the connector part.

It It was found that the coefficient of friction in the heavy Load of 5N decreases. This confirms the formation of a strong self-assembled monolayer with an alignment between the organic molecules.

<Evaluation of the friction coefficient>

The friction coefficient was measured on the coated substrate A and the uncoated substrate. For the condition of an actual application, the stamp of the measuring method had a contact shape equal to that of the connector part. As in 6 5N, a given load of 5N was applied to the substrate by the punch, and the substrate was slid and the force applied to the substrate (dynamic friction force) was measured with a slip tester (product of Yamazaki Seiki Laboratory). The friction coefficient is given as follows: coefficient of friction = dynamic friction force / contact load (equation 2).

The test conditions are as follows: contact weight: 5N, test speed: 24mm / min, displacement: 5mm (one direction and once), tin plated copper alloy stamp, having a hemisphere with a radius of 1.0mm at a contact portion with the substrate. 7A shows the result of the uncoated substrate, and 7B shows the result of the coated substrate A.

The The result shows that the coated substrate A according to the invention the dynamic friction coefficient to a large extent, on one third of that of the uncoated substrate.

Example 2: Connector

18 connector plugs made of tin-plated brass and 18 connector bushings made of a tin-plated copper alloy were provided. They were immersed in the 15% by volume nitric acid solution as well as the substrate and immersed in the 1 mM octadecanethiol-ethanol solution for 48 hours to form the self-assembled monolayer, and were purified by ultrasonic cleaning in ethanol. An Auger Electron Spectroscopy Meter (AES) confirmed the presence of a sulfur component in the connector part surface as in the spectrum of 8th shown.

It became the introductory force between the respective coated plug and the respective coated Socket measured. The locking pins to prevent each other solving the connector parts were for removed the measurement.

One EZGraph tester (product of Shimadzu Corporation) was used for insertion force measurement used. The connector socket connected to a load cell was from above with a feed rate of 25mm / min (according to JASOD 606) is moved in the direction of the connector plug part and fully connected. The EZGraph tester measured the load Regulation while the sliding into each other of the connector parts.

9 shows the load change when connecting a conventional connector. The male part of the male connector part is inserted into the spring from the female connector part or the female terminal, as in FIG 10 shown. When the male part enters the spring from the male connector, the load reaches a maximum value, which in 9 is denoted by A. When the male part is moved further into the socket by sliding, the load becomes a constant value, which is marked B. It is assumed that the load at B is correlated with the coefficient of friction of the sliding portion between the plug and the bushing.

11 shows the results of the load change of the invention. 11 shows a typical load change, similar to that of 9 , In 11 At the peak, the male part starts to enter the spring of the socket at the peak near a sliding distance of 0.1 mm. The constant load with a sliding distance of more than 0.12 mm corresponds to the sliding load between the plug and the socket. Since the connector pin testing pin is removed, the load is assumed to be constant.

11 shows that the value of the load from the coated connector portion or that with the self-assembled monolayer at about 0.12 mm is about two-thirds that of the uncoated connector portion. The invention confirmed the reduction of the insertion force for the actual connector.

The Connection of uncoated connector parts or those without the self-assembled monolayer points at one Sliding distance of over 0.12 mm an increase in load while the connection of the coated connector parts has a nearly constant value. It is assumed that the self-assembled monolayer is the Adhesion or friction of tin during can prevent the sliding of each connector part. The Maximum load near a sliding distance of 0.1 mm, where the male part enters the bush spring, also decreases. The self-assembled Monolayer has the effect of static coefficient of friction in terms of to reduce the onset of gliding.

Example 3: Substrate

It was pretreated with 10Ma% sulfuric acid instead of 15Ma% nitric acid Example 1 with the copper alloy substrate (NB109: product of Dowa Mining Co., Ltd.). The other processes were the same as those of example 1.

12A shows an XPS spectrum of the coated substrate. 12B shows an enlarged spectrum of the carbon C1s peak, and 12C shows an enlarged spectrum of the sulfur S2p peak. 13A shows an XPS spectrum of the uncoated substrate. 13B shows an enlarged spectrum of the carbon C1s peak, and 13C shows an enlarged spectrum of the sulfur S2p peak. XPS observation confirmed a component of octadecanethiol on the surface of the coated substrate.

Of the Friction resistance was for the substrates were measured with a load of 5N on the stamp. Of the Friction resistance of the coated substrate was 0.08, during the of the uncoated substrate was 0.17 and almost twice as high.

14 shows that the frictional resistance of the coated substrate at the load of 5N becomes 1 mΩ, which is almost the same as that of the uncoated substrate.

The Connector parts according to the invention do not require a special lever for adjusting the contact pressure. They are easy without cost increase produce and of small size. she increase not the contact resistance and they are low insertion force easily connect to each other, making them as connectors be applied by vehicles.

Claims (7)

Niedrigeinführkraft connector part, comprising a self-assembled monolayer on a sliding surface thereof. Connector part according to claim 1, wherein the sliding surface with Octadecanethiol is treated. Connector part according to claim 1 or 2, wherein the sliding surface before forming the self-assembled monolayer tin. Method of manufacturing a low insertion force connector part, comprising the step of forming a self-assembled monolayer a sliding surface from that. The method of claim 4, further comprising Step of removing a metal oxide on the sliding surface the molding of the self-assembled monolayer. The method of claim 5, wherein the metal oxide means Treating with acid-aqueous Solution removed becomes. Substrate for a low insertion force connector part, comprising a self-assembled monolayer on a sliding surface thereof.